Merge pull request #675 from AlgorithmWithGod/khj20006

[20250816] BOJ / G3 / 소가 길을 건너간 이유 6 / 권혁준

Author: ShinHeeEul

khj20006/202508/16 BOJ G3 소가 길을 건너간 이유 6.md

@@ -0,0 +1,159 @@
+```java
+import java.util.*;
+import java.io.*;
+
+class IOController {
+	BufferedReader br;
+	BufferedWriter bw;
+	StringTokenizer st;
+
+	public IOController() {
+		br = new BufferedReader(new InputStreamReader(System.in));
+		bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		st = new StringTokenizer("");
+	}
+
+	String nextLine() throws Exception {
+		String line = br.readLine();
+		st = new StringTokenizer(line);
+		return line;
+	}
+
+	String nextToken() throws Exception {
+		while (!st.hasMoreTokens()) nextLine();
+		return st.nextToken();
+	}
+
+	int nextInt() throws Exception {
+		return Integer.parseInt(nextToken());
+	}
+
+	long nextLong() throws Exception {
+		return Long.parseLong(nextToken());
+	}
+
+	double nextDouble() throws Exception {
+		return Double.parseDouble(nextToken());
+	}
+
+	void close() throws Exception {
+		bw.flush();
+		bw.close();
+	}
+
+	void write(String content) throws Exception {
+		bw.write(content);
+	}
+
+}
+
+class Point {
+	long x, y;
+	Point(long x, long y) {
+		this.x = x;
+		this.y = y;
+	}
+}
+
+public class Main {
+
+	static IOController io;
+
+	//
+
+	static final int INF = (int)1e9 + 7;
+	static final int[] dx = {0,1,0,-1};
+	static final int[] dy = {1,0,-1,0};
+
+	static int N, K, R;
+	static int[][][] cost;
+	static int[][] points;
+
+	public static void main(String[] args) throws Exception {
+
+		io = new IOController();
+
+		init();
+		solve();
+
+		io.close();
+
+	}
+
+	static void init() throws Exception {
+
+		N = io.nextInt();
+		K = io.nextInt();
+		R = io.nextInt();
+		cost = new int[N+1][N+1][4];
+		for(int i=0;i<R;i++) {
+			int a = io.nextInt();
+			int b = io.nextInt();
+			int c = io.nextInt();
+			int d = io.nextInt();
+			if(a == c) {
+				if(b+1 == d) {
+					cost[a][b][0] = cost[c][d][2] = 1;
+				}
+				else {
+					cost[a][b][2] = cost[c][d][0] = 1;
+				}
+			}
+			else {
+				if(a+1 == c) {
+					cost[a][b][1] = cost[c][d][3] = 1;
+				}
+				else {
+					cost[a][b][3] = cost[c][d][1] = 1;
+				}
+			}
+		}
+		points = new int[K][2];
+		for(int i=0;i<K;i++) points[i] = new int[]{io.nextInt(), io.nextInt()};
+
+	}
+
+	static void solve() throws Exception {
+
+		int ans = 0;
+		for(int[] point : points) {
+			int x = point[0], y = point[1];
+			int[][] dist = dijk(x, y);
+			for(int i=0;i<K;i++) {
+				int xx = points[i][0], yy = points[i][1];
+				if(dist[xx][yy] > 0) ans++;
+			}
+		}
+		io.write((ans/2) + "\n");
+
+	}
+
+	static int[][] dijk(int sx, int sy) {
+		Deque<int[]> deque = new ArrayDeque<>();
+		int[][] dist = new int[N+1][N+1];
+		for(int i=1;i<=N;i++) Arrays.fill(dist[i], INF);
+		deque.offer(new int[]{0, sx, sy});
+		dist[sx][sy] = 0;
+		while(!deque.isEmpty()) {
+			int[] cur = deque.pollFirst();
+			int d = cur[0], x = cur[1], y = cur[2];
+			for(int i=0;i<4;i++) {
+				int xx = x+dx[i], yy = y+dy[i];
+				if(xx<1 || xx>N || yy<1 || yy>N) continue;
+				int nextCost = d + cost[x][y][i];
+				if(dist[xx][yy] > nextCost) {
+					if(d == nextCost) {
+						deque.addFirst(new int[]{nextCost, xx, yy});
+					}
+					else {
+						deque.addLast(new int[]{nextCost, xx, yy});
+					}
+					dist[xx][yy] = nextCost;
+				}
+			}
+		}
+		return dist;
+	}
+
+}
+```